Disclaimer: The opinions, results, and conclusions are those of the authors, and no endorsement by the Ministry of Health and Long-Term Care or by the Institute for Clinical Evaluative Sciences is intended or should be inferred.

Grant Support: By an operating grant from the Canadian Institutes of Health Research (MOP 111150) and the Ontario Ministry of Health and Long-Term Care.

From the University of Toronto and Institute for Clinical Evaluative Sciences, Toronto; University of Western Ontario, London; McMaster University, Hamilton; University of Ottawa, Ottawa; Queen's University, Kingston; and Southlake Regional Health Centre, Newmarket, Ontario, Canada.

Rates of ICD implantation were similar in men and women (relative risk, 0.99 [95% CI, 0.97 to 1.02]; P = 0.60). However, women were significantly more likely to experience major complications by 45 days (odds ratio, 1.78 [CI, 1.24 to 2.58]; P = 0.002) and 1 year (hazard ratio [HR], 1.91 [CI, 1.48 to 2.47]; P < 0.001) after implantation. Occurrence of any major or minor complication was also increased in women at both 45-day follow-up (odds ratio, 1.50 [CI, 1.12 to 2.00]; P = 0.006) and 1-year follow-up (HR, 1.55 [CI, 1.25 to 1.93]; P < 0.001). After implantation, women were less likely than men to receive appropriate ICD shock (HR, 0.69 [CI, 0.51 to 0.93]; P = 0.015) or appropriate therapy via shock or antitachycardia pacing (HR, 0.73 [CI, 0.59 to 0.90]; P = 0.003). Total mortality among defibrillator recipients did not differ between men and women (HR, 1.00 [CI, 0.64 to 1.55]; P = 0.99).

Limitation:

The differential effects of sex on prereferral events were not examined.

Conclusion:

Although ICD implantation rates were similar after referral to an electrophysiologist, women who underwent ICD implantation had greater risks for complications and were less likely to experience appropriate ICD-delivered therapies than men.

Primary Funding Source:

Canadian Institutes of Health Research and Ontario Ministry of Health and Long-Term Care.